Podcaster: Dr. Al Grauer


Title: Travelers in the Night Eps. 121E & 122E: Close Approaches & Recycling Spacecraft

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

Description: Today’s 2 topics:

  • Richard Kowalski and Carson Fuls discovered 2015 EO & 2015 ET.
  • Our ability to recover from malfunctions allows scientists to make the best use of available funds.

Bio: Dr. Al Grauer is currently an observing member of the Catalina Sky Survey Team at the University of Arizona.  This group has discovered nearly half of the Earth approaching objects known to exist. He received a PhD in Physics in 1971 and has been an observational Astronomer for 43 years. He retired as a University Professor after 39 years of interacting with students. He has conducted research projects using telescopes in Arizona, Chile, Australia, Hawaii, Louisiana, and Georgia with funding from NSF and NASA.

He is noted as Co-discoverer of comet P/2010 TO20 Linear-Grauer, Discoverer of comet C/2009 U5 Grauer and has asteroid 18871 Grauer named for him.

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121E: Close Approaches

Slightly more than a day apart, my NASA funded Catalina Sky Survey teammates Richard Kowalski and Carson Fuls  found two small asteroids. Both of them can travel to much closer than the distance to our Moon from planet Earth.  Subsequently, telescopes around the world were employed to determine accurate paths and size estimates for both of them. 

The first, Asteroid 2015 EO orbits the Sun every 1.47 years on a path which goes from the orbit of Venus to out past that of Mars.  When Kowalski first spotted it, this 50 foot diameter asteroid was 4 million miles from Earth and was moving towards us at 9 miles/second.  Six days later it approached to about 3 lunar distances from Earth.  If it had been on an impact trajectory, we could have warned the people in danger to stay away from doors and windows. 

The second, Asteroid 2015 ET, orbits the Sun every 2.95 years.  When Fuls discovered this 50 foot diameter asteroid it was at nearly its closest point to Earth. After that it continued to move away from the Sun and Earth on a path that will take it 60% of the way to the planet Jupiter before it starts back towards the Earth again.

It is possible that either of these tiny asteroids could enter the Earth’s atmosphere in the distant future and release the energy of a small nuclear weapon.  We might expect such an event every 27 years or so.  

There are likely to be several million space rocks of this size which come close to planet Earth.  We now know more about two of them. 

122E: Recycling Spacecraft

In the early days of space exploration when a flight component failed the mission was over.  In recent history, there have been a few times when astronauts have repaired satellites and a number of instances of Earth bound engineers reprogramming malfunctioning spacecraft so that they could continue their scientific work. 

For more than 25 years the Hubble Space Telescope produced unprecedented scientific data. This was made possible during repair missions by astronauts using the space shuttle.

The NASA Kepler Spacecraft has discovered more than a thousand planets orbiting distant stars.  When the second of its 4 stabilizing gyroscopes failed it could not longer point well enough to continue this effort.  Fortunately, clever NASA engineers figured out how to use the radiation pressure from the Sun to act as the third gyroscope.   The reprogrammed Kepler is now studying new exoplanets, stars of various ages, star clusters, and active galaxies.

The Spitzer Spacecraft and The NEOWISE Spacecraft are continuing to make scientific discoveries after their infrared camera’s ran out of coolant by a clever reprogramming to extend their missions.   The malfunctioning NASA Wide-Field Infrared Explorer was reprogrammed to use its guide camera to determine the mass, compositions, and ages of more than 200 bright stars to a high degree of accuracy.  

Since the cost of developing and launching spacecraft far exceeds the cost of operating them for extended periods of time, our ability to recover from malfunctions allows scientists to make the best use of available funds.

For Travelers in the Night this is Dr. Al Grauer.

End of podcast:

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